chr1-209650120-T-C

Variant names:

Variant summary

Our verdict is Pathogenic. The variant received 12 ACMG points: 12P and 0B. PVS1PM2PP5_Moderate

The NM_000228.3(LAMB3):c.29-2A>G variant causes a splice acceptor, intron change. The variant allele was found at a frequency of 0.00000137 in 1,459,956 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Likely pathogenic (★).

Frequency

Genomes: not found (cov: 33)

Exomes 𝑓: 0.0000014 ( 0 hom. )

Consequence

LAMB3
NM_000228.3 splice_acceptor, intron

Scores

Splicing: ADA: 1.000

Clinical Significance

Likely pathogenic criteria provided, single submitter P:2

Conservation

PhyloP100: 4.37

Publications

2 publications found

Variant links:

Genes affected

LAMB3 (HGNC:6490): (laminin subunit beta 3) The product encoded by this gene is a laminin that belongs to a family of basement membrane proteins. This protein is a beta subunit laminin, which together with an alpha and a gamma subunit, forms laminin-5. Mutations in this gene cause epidermolysis bullosa junctional Herlitz type, and generalized atrophic benign epidermolysis bullosa, diseases that are characterized by blistering of the skin. Multiple alternatively spliced transcript variants that encode the same protein have been found for this gene. [provided by RefSeq, Jul 2008]

LAMB3 Gene-Disease associations (from GenCC):

junctional epidermolysis bullosa
Inheritance: AR Classification: DEFINITIVE Submitted by: Myriad Women’s Health
junctional epidermolysis bullosa Herlitz type
Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Ambry Genetics, Labcorp Genetics (formerly Invitae), Genomics England PanelApp, Orphanet, Laboratory for Molecular Medicine
junctional epidermolysis bullosa, non-Herlitz type
Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: PanelApp Australia, Genomics England PanelApp, Ambry Genetics
amelogenesis imperfecta type 1A
Inheritance: AD Classification: STRONG, MODERATE Submitted by: Labcorp Genetics (formerly Invitae), Ambry Genetics
amelogenesis imperfecta type 1
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
generalized junctional epidermolysis bullosa non-Herlitz type
Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

LAMB3 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Pathogenic. The variant received 12 ACMG points.

PVS1

Splicing +-2 bp (donor or acceptor) variant, LoF is a know mechanism of disease, No cryptic splice site detected. Exon removal results in frameshift change.

PM2

Very rare variant in population databases, with high coverage;

PP5

Variant 1-209650120-T-C is Pathogenic according to our data. Variant chr1-209650120-T-C is described in ClinVar as Likely_pathogenic. ClinVar VariationId is 188740.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
LAMB3	NM_000228.3 link	c.29-2A>G		splice_acceptor_variant, intron_variant	Intron 2 of 22	ENST00000356082.9	NP_000219.2	Q13751A0A0S2Z3R6

Ensembl

Gene	Transcript	HGVSc	Effect	Exon rank	TSL	MANE	Protein	UniProt
LAMB3	ENST00000356082.9 link	c.29-2A>G	splice_acceptor_variant, intron_variant	Intron 2 of 22	1	NM_000228.3	ENSP00000348384.3	Q13751
LAMB3	ENST00000367030.7 link	c.29-2A>G	splice_acceptor_variant, intron_variant	Intron 2 of 22	1		ENSP00000355997.3	Q13751
LAMB3	ENST00000391911.5 link	c.29-2A>G	splice_acceptor_variant, intron_variant	Intron 1 of 21	1		ENSP00000375778.1	Q13751
LAMB3	ENST00000415782.1 link	c.29-2A>G	splice_acceptor_variant, intron_variant	Intron 2 of 5	2		ENSP00000388960.1	Q5THA1

Frequencies

GnomAD3 genomes

Cov.:

GnomAD2 exomes

AF:

0.00

AC:

AN:

246812

AF XY:

0.00

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000137

AC:

AN:

1459956

Hom.:

Cov.:

AF XY:

0.00000138

AC XY:

AN XY:

726126

show subpopulations

African (AFR)

AF:

0.0000598

AC:

AN:

33442

American (AMR)

AF:

0.00

AC:

AN:

44518

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26074

East Asian (EAS)

AF:

0.00

AC:

AN:

39654

South Asian (SAS)

AF:

0.00

AC:

AN:

85966

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53240

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5464

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

1111296

Other (OTH)

AF:

0.00

AC:

AN:

60302

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.475

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

Cov.:

Alfa

AF:

0.00

Hom.:

Bravo

AF:

0.00000378

ESP6500AA

AF:

0.000227

AC:

ESP6500EA

AF:

0.00

AC:

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

Junctional epidermolysis bullosa gravis of Herlitz

Pathogenic:1

Apr 01, 2014

Counsyl

Significance:Likely pathogenic

Review Status:no assertion criteria provided

Collection Method:literature only

This submission and the accompanying classification are no longer maintained by the submitter. For more information on current observations and classification, please contact variantquestions@myriad.com. -

not provided

Pathogenic:1

Sep 03, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

ClinVar contains an entry for this variant (Variation ID: 188740). Disruption of this splice site has been observed in individual(s) with junctional epidermolysis bullosa (PMID: 21801158). This variant is not present in population databases (gnomAD no frequency). This sequence change affects an acceptor splice site in intron 2 of the LAMB3 gene. It is expected to disrupt RNA splicing. Variants that disrupt the donor or acceptor splice site typically lead to a loss of protein function (PMID: 16199547), and loss-of-function variants in LAMB3 are known to be pathogenic (PMID: 11023379, 16473856). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_addAF

Pathogenic

0.60

BayesDel_noAF

Pathogenic

0.18

CADD

Pathogenic

(source)

DANN

Uncertain

0.99

Eigen

Pathogenic

1.0

Eigen_PC

Pathogenic

0.89

FATHMM_MKL

Uncertain

0.95

PhyloP100

4.4

GERP RS

5.4

Mutation Taster

=0/100

disease causing (ClinVar)

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

dbscSNV1_ADA

Pathogenic

1.0

dbscSNV1_RF

Pathogenic

0.91

SpliceAI score (max)

0.96

Details are displayed if max score is > 0.2

DS_AL_spliceai

0.96

Position offset: -2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over